2378 results about "Ascorbic acid" patented technology

The invention discloses a synthesis method of vitamin C ethyl ether, and belongs to the technical field of vitamin derivative synthesis. The synthesis method comprises the following steps: adding vitamin C, benzaldehyde and a catalyst into a first organic solvent, carrying out an aldolization reaction, adding an organic alkali after the aldolization reaction is finished, carrying out a neutralization reaction, adding an alkylation reagent, carrying out an alkylation reaction, and removing the first organic solvent after the alkylation reaction is finished, so as to obtain the vitamin C benzaldehyde. The preparation method comprises the following steps: adding a first organic solvent into a first organic solvent, pulping, filtering, collecting filter residues, washing and drying to obtain 5, 6-O-benzyl-3-O-ethyl-L-ascorbic acid, carrying out hydrogenation deprotection on the 5, 6-O-benzyl-3-O-ethyl-L-ascorbic acid, filtering after hydrogenation deprotection, collecting filtrate, crystallizing, collecting precipitate, washing and drying to obtain the 5, 6-O-benzyl-3-O-ethyl-L-ascorbic acid. The vitamin C ethyl ether is obtained. The synthesis method provided by the invention is simple to operate and high in production efficiency, and the obtained vitamin C ethyl ether is high in yield and purity.

The invention relates to the technical field of environmental materials and water treatment, in particular to a graphene amino silica gel composite adsorbent for heavy metal wastewater treatment and a preparation method thereof.The graphene amino silica gel composite adsorbent is prepared from # imgabs0 nanoparticles, an amino-functionalized silicon dioxide coating layer, carboxylated reduced graphene oxide, a polydopamine modification layer and tetraethyl orthosilicate; the coating is prepared from the following raw materials: 3-aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, N-((4-vinyl benzyl) amino) diacetic acid, chitosan, beta-cyclodextrin, hexadecyl trimethyl ammonium bromide, polyethylene glycol, L-ascorbic acid, 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide hydrochloride and N-hydroxysuccinimide. The composite adsorbent shows excellent adsorption performance on various heavy metal ions, and the adsorption performance is far higher than that of traditional adsorption materials and existing composite adsorbents.

The invention discloses battery-grade iron phosphate and a preparation method and application thereof.The method comprises the steps that 1, waste iron sheets are ground into iron powder to be mixed with a phosphoric acid solution, reduced iron powder, ascorbic acid and chloramine-T are added in the mixing process for a reaction, solid-liquid separation is conducted after the reaction, a ferrous dihydrogen phosphate solution is obtained, and the pH of the ferrous dihydrogen phosphate solution is 1.5-3.0; and (2) oxidizing the ferrous dihydrogen phosphate solution into iron phosphate in one step by adopting an oxidizing agent, carrying out solid-liquid separation to obtain an iron phosphate solid, washing and drying the iron phosphate solid, and roasting in an inert atmosphere environment to obtain the battery-grade iron phosphate. According to the invention, the use of high-cost reduced iron powder is reduced, and the produced iron phosphate has the characteristics of high iron-phosphorus ratio and high tap density, has certain carbon content, and has a wide prospect in the application of lithium iron phosphate.

The invention relates to a whitening composition containing pH-sensitive oxidized resveratrol hydrogel and application. The whitening composition is a composition of oxidized resveratrol hydrogel, a hydrolyzed opuntia pear flower extract and a mexican agastache rugosus flower / leaf / stem extract in a weight ratio of 1: (0.6-0.7): (0.01-0.02). The oxidized resveratrol hydrogel is prepared from the following raw materials in percentage by weight: 1 to 3 percent of oxidized resveratrol, 1 to 3 percent of 3-o-ethyl ascorbic acid, 15 to 20 percent of butanediol, 0.1 to 0.5 percent of sodium alginate, 0.1 to 0.5 percent of carboxymethylcellulose, 0.3 to 0.8 percent of calcium chloride and the balance of water. The three components of the whitening skincare product have a remarkable synergistic effect in the whitening aspect, the skin color can be jointly improved from different mechanisms, and meanwhile, the mildness and the safety are considered.

Provided are a whitening and freckle-removing composition, a gel, a preparation method therefor, and a use thereof, relating to the technical field of skin-care products. The whitening and freckle-removing composition comprises tranexamic acid, nicotinamide, 4-butylresorcinol, licorice extract, 3-o-ethyl ascorbic acid, and glutathione. For the whitening composition, by inhibiting the activity of tyrosinase, blocking the transfer of melanin from melanocytes to keratinocytes, and inhibiting the formation and accumulation of melanin by means of multiple mechanisms including oxidation resistance, and by means of the synergistic action of all components, cosmetic benefits of whitening and freckle-removing are achieved. The whitening and freckle-removing gel has a simple preparation method, has a mild and non-sensitizing formula, is safe and non-irritating, and is suitable for large-scale production and application.

The invention discloses a seed priming method for improving early-stage disease resistance of pepper seeds, which belongs to the field of agricultural planting and comprises the following steps: S1, pre-cleaning: soaking the seeds with sodium hypochlorite and then cleaning the seeds with sterile deionized water; s2, pulse phosphorylation activation treatment: adding seeds and an activation solution into a pressure-resistant polypropylene container connected with a vacuum pipeline, sealing, vacuumizing to-0.08 MPa, maintaining for 5-10 minutes, then recovering to normal pressure, transferring to a constant-temperature oscillator, and carrying out phosphorylation activation treatment; s3, immune training treatment: transferring the seeds subjected to phosphorylation activation treatment to an initiation solution containing UV-inactivated phytophthora capsici spore suspension and H2O2, and carrying out intermittent ventilation treatment; s4, stabilizing treatment: transferring the seeds subjected to immune training treatment into an ascorbic acid solution for treatment, filtering, and drying in the shade to obtain the pepper seeds. According to the invention, the problem of immune response interruption caused by insufficient signal intensity and fast protein turnover when a simulated environment is used for excitation in the prior art is solved.

The invention discloses bacillus subtilis ZX-5 for promoting growth of gleditsia sinensis under salt stress and application of the bacillus subtilis ZX-5, and relates to the technical field of microorganisms. The invention discloses bacillus subtilis ZX-5 for promoting growth of gleditsia sinensis under salt stress, and the bacillus subtilis ZX-5 is preserved in the China General Microbiological Culture Collection Center (CGMCC), and the preservation number is CGMCC No.31648. The result of the embodiment shows that the bacillus subtilis ZX-5 promotes the ground diameter growth rate and seedling height growth rate of the gleditsia sinensis to be improved under salt stress, and promotes the total root length and root tip number of the gleditsia sinensis root system to be increased; the surface area of the gleditsia sinensis root is increased under the stress of 150mM salt. The activities of Chinese honey locust superoxide dismutase, peroxidase, catalase and ascorbic acid peroxidase are promoted to be enhanced under the stress of salt; the contents of ascorbic acid and reduced glutathione in the gleditsia sinensis are promoted to be increased under the stress of salt; the content increase of soluble protein, soluble sugar and free proline in the gleditsia sinensis is promoted.

The invention relates to the technical field of total phosphorus detection, in particular to a method for determining total phosphorus in water, which comprises the following steps: 1) digestion treatment: adding an oxidant into a water sample to be detected, and then performing microwave digestion treatment to obtain digested water; a molybdate reagent is added into the digested water, then an improved ascorbic acid solution is added, a chromogenic reaction is completed at the set temperature, and the improved ascorbic acid solution is obtained by mixing an ascorbic acid solution and sodium ethylene diamine tetracetate; measuring the concentration: measuring the absorbance value of the obtained color development product by using a spectrophotometer and a long-optical-path cuvette; and drawing a standard curve: using a phosphorus standard solution as a quality control sample, adding a plurality of calibration points in a low-concentration interval of 0.0-0.1 mg / L, carrying out colorimetric determination, and establishing quadratic equation fitting according to absorbance and concentration so as to determine the total phosphorus content of the water sample to be detected, and the method has the advantages of high sensitivity and good accuracy in total phosphorus testing.

The invention belongs to the technical field of rare and precious metal recovery, and particularly relates to a method for recovering metallic silver from waste crystalline silicon battery pieces, which comprises the following steps: (1) putting the waste crystalline silicon battery pieces into an inorganic alkali aqueous solution for soaking reaction to obtain an aluminum-containing solution and dealuminized crystalline silicon pieces; (2) adding the dealuminized crystal silicon wafer into a mixed solution of organic acid and hydrogen peroxide for soaking reaction, filtering and washing to respectively obtain silver-containing filtrate and a silver-removed silicon wafer; (3) carrying out chlorination precipitation reaction on the silver-containing filtrate and a chlorine source, filtering and drying to obtain silver chloride powder; (4) adding silver chloride powder into an ammonia water solution, heating and stirring to completely dissolve silver chloride to obtain a silver-ammonia solution; (5) adding PVP (Polyvinyl Pyrrolidone) into the silver-ammonia solution, heating and stirring until the PVP is completely dissolved, adding ascorbic acid, and carrying out reduction reaction at room temperature to obtain metal silver powder precipitate; and filtering, washing and drying the precipitate to obtain the spherical silver powder. According to the method, the silver recovery efficiency is high, the spherical nanoscale silver powder can be prepared, and the purity is high.

The invention discloses a cyclic peptide compound as well as a preparation method and application thereof, belongs to the field of polypeptide synthesis and application, and particularly relates to full-protection peptide resin prepared by solid-phase synthesis. Carrying out cutting and monocyclization on the full-protection peptide resin to obtain monocyclic peptide; the monocyclic peptide is subjected to binary cyclization treatment to obtain a cyclic peptide compound Cyclo (His-Lys-Cys-Gly-His-Lys-Cys-Gly-, and a disulfide bond is in bridge connection with Cysamp; and the binary cyclization is cyclized under the action of iodine methanol and ascorbic acid. The cyclopeptide compound prepared by the invention has the advantages of low toxicity, good stability, good antioxidant effect and good anti-inflammatory effect, and the expression of type I collagen can be improved. Therefore, the invention has the advantages of low toxicity, good stability, good antioxidant effect and good anti-inflammatory effect, and can improve the expression of the type I collagen.

The invention discloses a collagenase mutant, a gene segment, a recombinant plasmid, a recombinant expression system, a collagen peptide, and a preparation method and application thereof, and belongs to the field of gene engineering and fermentation engineering. The collagenase mutant KT513 with high specific activity is obtained through recombinant expression in a trichoderma reesei host, and the enzyme activity of the collagenase mutant KT513 reaches 7423.18 U / mL. The optimum action pH of the enzyme is 3.0, the red snapper scale collagen can be subjected to enzymolysis in the pH range of 3.0-5.0, and the enzyme has excellent enzymolysis activity. After the collagenase mutant KT513 is subjected to enzymolysis at 40 DEG C for 4 hours, the extraction rate of fish scale collagen reaches 80.09%, and the prepared collagen peptide has good antioxidant activity. When the addition concentration is 10 mg / mL, the in-vitro scavenging activity of the prepared collagen peptide on hydroxyl radicals reaches 99.26% and is equivalent to that of ascorbic acid, and the collagen peptide has a wide application prospect in preparation of antioxidant preparations.

The invention belongs to the technical field of catalyst preparation, focuses on a high-entropy alloy nanowire catalyst, and mainly relates to a preparation method and application of an AuCuAgPtNi catalyst. A one-pot wet chemical method is innovatively adopted, a 4-aminopyridine solvent and metal precursors of gold, copper, silver, platinum and nickel are fully and evenly mixed and placed in an oil bath pot at the temperature of 90 DEG C, then a reducing agent ascorbic acid is rapidly added, after specific reaction time, washing, drying and other operations are sequentially carried out, and the high-entropy alloy nanowire AuCuAgPtNi catalyst can be successfully prepared. The preparation method disclosed by the invention has the remarkable advantages of simple process, simple steps, convenience in operation and the like. In an alkaline environment, the prepared nanowire-shaped high-entropy alloy AuCuAgPtNi catalyst shows extremely excellent catalytic activity and selectivity for catalytic degradation of waste plastic polylactic acid, the waste plastic can be efficiently upgraded and converted into pyruvic acid, a new way is opened up for resource utilization of the waste plastic, and the application prospect is wide. The method has a wide application prospect in the fields of environmental protection and resource recovery.

The invention belongs to the technical field of battery materials, and particularly discloses preparation and application of a strontium lanthanum manganate-coated lithium ferric manganese phosphate composite material, and the method comprises the following steps: firstly, preparing strontium lanthanum manganate by adopting a lanthanum source, a strontium source and a manganese source as raw materials; respectively adding a lithium source, a phase transfer agent, a phosphorus source, L-ascorbic acid, an iron source and a manganese source into a solvent, and preparing a lithium ferric manganese phosphate precursor by using a solvothermal method; the lithium ferric manganese phosphate material is coated twice through strontium lanthanum manganate and carbon. According to the invention, strontium lanthanum manganate is used as a coating material, and the addition of lanthanide elements improves the crystal stability of lithium ferric manganese phosphate, keeps the integrity of an olivine-type structure, and avoids capacity fading caused by structure collapse, thereby improving the cycle stability of the lithium ion battery.

The invention belongs to the technical field of stainless steel surface treatment, and particularly relates to a stainless steel passivation solution and a preparation method thereof. The water-based cutting fluid is prepared from the following raw materials: cerium salt, copper sulfate, citric acid, sodium dihydrogen phosphate, ammonium molybdate, sodium tungstate, aminated-silane modified SiO2 nanoparticles, polyethylene glycol, L-ascorbic acid, polyaspartic acid, an anti-settling agent, a surfactant and the balance of deionized water. According to the invention, a three-dimensional network skeleton is constructed by using aminated-epoxy group silane modified SiO2 nanoparticles, so that the problem of weak interface bonding force of a traditional passivation layer is solved; according to the formula, the proportion of biodegradable components such as citric acid and polyaspartic acid is extremely high, cerate adopts a low-toxicity rare earth compound, molybdenum / tungsten elements are fixed in a stable oxide form, the dosage of EDTA is remarkably reduced through a compounding technology, residual ions are adsorbed in combination with a three-dimensional network, and the balance of environment friendliness and long-acting corrosion resistance is achieved.

The invention relates to the field of foaming materials, in particular to a low-solvent-residue expandable polystyrene material and a preparation method thereof. The expandable polystyrene material with low solvent residue comprises the following raw materials in percentage by weight: 0.35-0.45% of a free radical initiation system, 0.35-0.45% of S, S, S, S, S, S, S, S, S, S, S, S, S, S, S According to the present invention, the material comprises, by weight, 0.1-0.15% of S, S '-bis (alpha, alpha'-dimethyl-alpha ''-acetoxy) trithiocarbonate, 0.15-0.2% of ascorbic acid, 0.1-0.2% of a nucleating agent, 0.2-0.3% of a suspending agent, 0.001-0.003% of an emulsifier, 5-6% of a foaming agent, 0.15-0.25% of a plasticizer, 0.001-0.002% of hydroxyethyl cellulose, 0.05% of sodium phosphate, 0.1-0.2% of zinc stearate, and 0.1-0.2% of glyceryl stearate, the obtained material has low solvent residue, meets food safety requirements, and is suitable for food packaging.

The invention relates to the technical field of sodium ion battery positive electrode materials, and discloses a preparation method and application of a carbon-coated sodium ferric sulfate positive electrode material, and the preparation method comprises the following steps: (1) adding an iron source into an aqueous solution containing an organic acid, and stirring, the organic acid being ascorbic acid and / or citric acid; adding a sodium source or the sodium source and a sulfuric acid source, and stirring; (2) finally adding a carbon source, dropwise adding absolute ethyl alcohol while stirring, vacuumizing after dropwise adding, and continuously stirring for 2-4 hours to obtain a mixed solution; and (3) carrying out closed spray drying on the mixed solution, and calcining in an inert atmosphere to obtain the carbon-coated sodium ferric sulfate positive electrode material. According to the preparation method, coating of the carbon material is achieved in a closed spray drying mode, the conductivity of sodium ferric sulfate is greatly improved, in the whole preparation process, contact with oxygen is avoided, organic acid with an anti-oxidation effect is avoided, ferrous iron is prevented from being oxidized, and then the electrochemical performance can be further improved.

The invention relates to the technical field of zinc glycinate production, and provides a zinc glycinate chelate preparation method, which comprises: (1) pre-mixing glycine and nano zinc oxide, adding into water, and carrying out microwave treatment and ultrasonic-assisted synergistic treatment to prepare a glycine suspension; (2) adding L-ascorbic acid, stirring, maintaining the temperature at 58-62 DEG C for 30-40 minutes, heating to 74-80 DEG C, and maintaining the temperature at 74-80 DEG C for 2-3 hours; and (3) cooling to room temperature, standing, centrifugally separating, and drying to obtain the zinc glycinate chelate. According to the preparation method of the glycine zinc chelate, the production cost is effectively reduced and the production efficiency is improved under the condition that the purity and the stability of the product are ensured.

A fracturing fluid for fracturing subterranean formations comprising ascorbic acid. The fracturing fluid can use ascorbic acid to delay increases in viscosity until desired. The viscosity increase can then be maintained over a period of time to perform fracturing operations.

The invention discloses an arbutin derivative 6-O-Caffeoylbutin as well as a preparation method and application of the arbutin derivative 6-O-Caffeoylbutin. The structural formula of a 6-O-Caffeoylbutin compound is shown as a formula (I): # imgabs0. The invention also discloses application of the arbutin derivative (6-O-Caffeoylbutin) disclosed by the invention in preparation of an antioxidant preparation. According to the invention, the 6-O-Caffeoylbutin extracted for the first time shows excellent antioxidant activity, the ability of the 6-O-Caffeoylbutin to remove ABTB < + > free radicals is stronger than that of ascorbic acid and beta-arbutin, and a material basis is provided for development of novel antioxidants.

The invention provides a preparation method and application of magnesium L-threonate, and belongs to the technical field of medicines. The preparation method comprises the following steps: dissolving L-ascorbic acid in water, adding magnesium hydroxide and alkaline magnesium carbonate, stirring, dropwise adding hydrogen peroxide, heating, stirring and reacting, filtering a product, purifying and concentrating by temperature-sensitive molecularly imprinted hydrogel while the product is hot, adding an ethanol water solution into a concentrated solution, standing, crystallizing, filtering, washing and drying to obtain the magnesium L-threonate. And cooling the temperature-sensitive molecularly imprinted hydrogel after adsorption to room temperature, washing and repeatedly using the temperature-sensitive molecularly imprinted hydrogel. The magnesium L-threonate is simple in preparation method, high in purity and high in yield, meanwhile, the slow-release magnesium L-threonate is prepared, and the magnesium L-threonate is low in toxicity, good in biocompatibility, large in drug loading capacity, low in economic cost and good in drug effect and has wide application prospects in preparation of anti-depression drugs.

The present invention discloses a method for preparing highly dispersible submicron spherical palladium powder. The method comprises the following steps: first, weighing solid palladium nitrate and dissolving it in dilute nitric acid to prepare a dilute palladium nitrate solution; then dissolving a reducing agent in deionized water to obtain a reducing solution; then weighing a dispersant and an additive and dissolving them in deionized water to obtain a mixed base solution; and then mixing the three to obtain a reaction slurry containing palladium powder. The mixture is then filtered, washed, and dried to obtain submicron spherical palladium powder particles. The present invention adopts a liquid phase reduction method to reduce the palladium nitrate solution with ascorbic acid or hydrazine hydrate as a reducing agent to prepare the submicron spherical palladium powder. An organic polymer dispersant and a small molecule alcohol additive are simultaneously added to the base solution in a symmetrical manner. While ensuring the yield of palladium powder, the particle growth process and dispersibility are well controlled. The prepared palladium powder particles are spherical and highly dispersed, with a particle size of 100 to 600 nm.

The invention belongs to the field of synthesis of nano materials, and particularly relates to a core-shell structure gold nano star and a preparation method and application thereof, and the core-shell structure gold nano star comprises a first gold nano star containing a metal sulfide shell layer and a second gold nano star containing a metal oxide shell layer. The preparation method comprises the following steps: firstly preparing a gold nano star core solution, and then respectively adding different precursors to prepare two core-shell structure gold nano stars. The method has the advantages of simple synthesis conditions and non-toxic reagents. The core-shell structure gold nanostars are used for preparing a detection solution based on a buffer solution, a color developing agent and an oxidizing agent, the detection solution reacts with antioxidants, a data matrix is constructed by measuring absorbance changes and is analyzed, single, binary and ternary combinations of various antioxidants such as ascorbic acid and glutathione can be accurately distinguished, and the detection accuracy is improved. The application prospect in the fields of biomolecules and food detection is good.

The invention provides a preparation method and application of red nano-selenium particles, and relates to the technical field of nano-medicines.The preparation method comprises the steps that sodium selenite is dissolved in ultrapure water, silicate microspheres containing copper, zinc and aluminum are added, the pH value is 4.8, 1.5 M of ascorbic acid solution is dropwise added while stirring, the temperature is increased till solid ascorbic acid is added, the pH value is adjusted through NaOH, and nano-selenium suspension liquid is obtained through stirring reaction; the preparation method comprises the following steps: mixing and stirring a nano-selenium suspension, a sodium alginate sulfydryl graphene oxide mixture and a chitosan oligosaccharide citric acid buffer solution, centrifugally washing, and freeze-drying to obtain red nano-selenium particles, and preparing the copper-zinc-containing aluminosilicate microspheres through mesoporous template calcination and copper-zinc co-doping. The red nano-selenium particles prepared by the method have a core-shell structure, uniform particle size, high oxidation resistance and remarkable interface bonding strength.

The invention relates to the field of cell biology, and particularly discloses a method for preparing mesoderm progenitor cells from human pluripotent stem cells and an induced differentiation culture medium of the mesoderm progenitor cells. The method comprises the following steps: inoculating human pluripotent stem cells in a single cell state into a culture dish covered with matrigel; and inducing the human pluripotent stem cells to be differentiated into the mesoderm progenitor cells within 1-3 days by using the mesoderm progenitor cell induced differentiation culture medium. Wherein the mesoderm progenitor cell induced differentiation culture medium is composed of a basic culture medium and an additive, and the additive contains a B-27 additive, non-essential amino acid, glutamine, ascorbic acid, polyvinyl alcohol, a GSK-3 inhibitor and a CDK8 inhibitor. According to the method, the human pluripotent stem cells are subjected to induced differentiation by using the mesoderm progenitor cell induced differentiation culture medium with specific composition, the method does not depend on cloning of the pluripotent stem cells, a large number of high-uniformity mesoderm progenitor cells can be obtained through induced differentiation within 1-3 days, the induction efficiency is high, and the stability is high.

The invention discloses a synthesis process of vitamin C ethyl ether, and belongs to the technical field of vitamin C derivative synthesis. The process comprises the following steps: taking L-ascorbic acid as a raw material, adding acetone, anhydrous cupric sulfate and acetyl chloride, and reacting for 1-2 hours at 38-40 DEG C under the protection of nitrogen to obtain a vitamin C protector; adding alkali, water, an alkylating reagent and absolute ethyl alcohol into the reaction product, reacting for 3 hours at 75-78 DEG C under the protection of nitrogen, and performing reduced pressure distillation to obtain a vitamin C protector etherate; and finally, hydrolyzing by using cationic resin, removing a protecting group, and recrystallizing by using ethyl acetate to obtain the vitamin C ethyl ether. Through the synergistic catalysis of anhydrous cupric sulfate and acetyl chloride, the reaction time is remarkably shortened, and the product purity and yield are improved. Through detection, the product purity is more than 99.5%, the total yield can reach more than 80%, and an efficient and economical method is provided for industrial production of vitamin C ethyl ether.

The invention relates to the technical field of bacterium enrichment nutrient solutions, in particular to a bacterium enrichment nutrient solution for fermentation and a preparation method of the bacterium enrichment nutrient solution. The culture medium is prepared from the following raw materials in parts by weight: maltodextrin, crystalline glucose, low-pigment yeast extract powder, refined soy peptone, dipotassium phosphate, monopotassium phosphate, magnesium sulfate heptahydrate, sodium chloride, phytic acid, L-ascorbic acid, manganese sulfate monohydrate, biotin, thiamine hydrochloride and choline chloride. Through a double-carbon-source structure, maltodextrin and crystalline glucose cooperate, metabolic oscillation is avoided, and the energy utilization rate is increased; the low-pigment yeast extract powder and the refined soy peptone are complementary, so that the rapid growth requirement of thalli is met; phytic acid is chelated with metal ions to prevent precipitation, L-ascorbic acid is used for resisting oxidation, and biotin and thiamine activate a coenzyme pathway to realize accurate regulation and control of a metabolic network.

The invention discloses a bimetallic Ag and Pd loaded WO3 material and a preparation method thereof, and relates to the technical field of sensor material preparation, and the preparation method comprises the following steps: 1, dissolving a tungsten source in an ethanol solution, mixing, hydrolyzing, aging, precipitating, washing, drying, calcining and cooling; 2, adding deionized water, adding a silver source solution and a palladium source, adding ascorbic acid, and stirring; 3, centrifuging, washing with ethanol and deionized water, and drying; 4, selecting a gold interdigital electrode with aluminum oxide ceramic as a substrate as a base electrode material, dipping the WO3 nano-particle dispersion liquid by using a line drawing pen, and uniformly coating the WO3 nano-particle dispersion liquid on the surface of the interdigital electrode; and 5, electrode drying and heat treatment. The efficient gas sensing material is prepared through the preparation method which is easy to operate, environmentally friendly and economical, and the gas sensing material has the advantages of being high in sensitivity, rapid in response, good in selectivity and the like at the low working temperature.

The invention belongs to the technical field of bioengineering, and particularly relates to a sucrose phosphorylase mutant and application thereof in synthesis of 2-O-alpha-D-glucopyranosyl-L-ascorbic acid. The sucrose phosphorylase mutant is obtained by simultaneously mutating multiple sites of amino acids at the 91st site, the 154th site, the 185th site, the 323rd site and the 424th site of wild sucrose phosphorylase derived from Bifidobacterium pseudolongum, so that the efficiency of producing 2-O-alpha-D-glucopyranosyl-L-ascorbic acid by taking sucrose and vitamin C as raw materials is remarkably improved; only 15 hours are needed for completely catalyzing 1.2 M of vitamin C to produce 2-O-alpha-D-glucopyranosyl-L-ascorbic acid; and the yield of the 2-O-alpha-D-glucopyranosyl-L-ascorbic acid reaches 358 g / L. Therefore, the 2-O-alpha-D-glucopyranosyl-L-ascorbic acid has an important application value in the field of production of the 2-O-alpha-D-

The invention belongs to the technical field of preparation of biological materials, and particularly discloses a sea cucumber flower self-assembled polypeptide-iron nano-carrier as well as a preparation method and application of the sea cucumber flower self-assembled polypeptide-iron nano-carrier. The preparation method comprises the following steps: dissolving freeze-dried sea cucumber flower powder in deionized water, adjusting the pH value to be alkaline, heating and stirring, centrifuging, discarding the precipitate, adjusting the pH value to be acidic, centrifuging, collecting the precipitate, and freeze-drying to obtain sea cucumber flower protein powder; preparing a reaction solution, adding simulated gastric juice and simulated intestinal juice, stirring for reaction, inactivating protease, centrifuging, taking supernatant, and freeze-drying to obtain sea cucumber flower self-assembled polypeptide; the preparation method comprises the following steps: preparing a solution from sea cucumber, adding FeCl2. 4H2O and ascorbic acid, adjusting the pH value to be acidic, carrying out heating reaction, centrifuging, discarding the supernatant, and freeze-drying to obtain the sea cucumber flower self-assembled polypeptide-iron nano-carrier. The invention discloses a sea cucumber flower self-assembled polypeptide-iron nano-carrier as well as a preparation method and application thereof. The carrier can promote absorption of an organism to iron, a relatively high iron ion release rate is maintained in an intestinal environment, and the in-vivo bioavailability of iron ions is improved.

The invention provides high-performance silver powder suitable for TOPCon battery fine grid silver paste, a preparation method of the high-performance silver powder and the silver paste, and belongs to the technical field of photovoltaic materials. The preparation method comprises the steps that a silver salt solution and a composite reducing agent are mixed, a first-stage hydrothermal reaction is carried out at the first temperature, a second-stage hydrothermal reaction is carried out at the second temperature, and silver powder is obtained after centrifugation, washing and drying; wherein the composite reducing agent is selected from a mixture of two of potassium tartrate, sodium sulfite and ferrous sulfate. According to the method, gradual growth and crystallinity improvement of silver crystal nucleuses are achieved through two-stage heating, particle aggregation or uneven morphology caused by rapid reduction is avoided, in addition, the adopted composite reducing agent combination is remarkably superior to a single reducing agent (such as ascorbic acid), and the morphology and particle size distribution of the silver powder can be more accurately regulated and controlled.